Laminated synthetic resin bottle, injection molding device, and process for molding a laminated preform

ABSTRACT

A problem to be solved by this invention is to control the above-described problem of delamination in the laminated and biaxially drawn, blow molded bottle. A major means of this invention to solve this problem is a biaxially drawn, blow molded bottle characterized in that vertical connecting zones having no intermediate layer and having substrate layers welded directly with each other are formed in parallel in a circumferential direction and in a plural number along an axial direction of the bottle and are disposed on both right and left sides of each intermediate layer segment to be formed in this height range, and that horizontal connecting zones having no intermediate layer and having substrate layers welded directly with each other are also formed in parallel in an axial direction and in a plural number along a circumferential direction of the bottle and are disposed on both upper and lower sides of each intermediate layer segment to be formed, thus allowing the intermediate layer to be segmentalized in the circumferential and axial directions by both the vertical and horizontal connecting zones.

This is a Divisional of application Ser. No. 13/001,212 filed Dec. 23,2010, which is the National Stage of PCT/JP2009/061820 filed on Jun. 29,2009, and claims the benefit of Japanese Patents No. 2008-171870 filedJun. 30, 2008 and No. 2008-171868 filed Jun. 30, 2008. The disclosure ofthe prior applications is hereby incorporated by reference herein in itsentirety.

TECHNICAL FIELD

This invention relates to a laminated synthetic resin bottle, which hasan intermediate layer laminated with a main resin and which is made bybiaxial drawing and blow molding, a process for molding a laminatedpreform which is a primary molded product for the bottle, and aninjection molding device used to mold this preform.

BACKGROUND ART

The biaxially drawn and blow molded bottles made of such a resin aspolyethylene terephthalate (hereinafter referred to as PET) are now inuse in various fields including beverages, foods, and cosmetics.Especially in those fields requiring a gas barrier property, use is madeof laminated bottles in which an intermediate gas barrier layer of anylon resin or a copolymeric resin of ethylene vinyl alcohol islaminated with layers of the main PET resin.

Patent document 1 discloses a biaxially drawn and blow molded bottle inwhich a layer of such a gas barrier resin has been laminated with thelayers of the PET resin, and a process for molding a laminated preformin a shape of a test tube, which is a primary molded product used tomold the laminated bottle. FIGS. 20 and 21 show representative examplesof such a bottle and a preform. The bottle 601 shown in FIG. 20comprises a neck 602, a neck ring 603, a cylindrical body 605, and abottom 606. In a height range excluding an upper portion of the neck 602and the bottom 606, an intermediate layer 613 of the nylon resin havinga gas barrier property is sandwiched between an outer layer 611 and aninner layer 612 both made of the PET resin.

The bottle 601 can be molded by biaxially drawing and blow molding thepreform 501 shown in FIG. 21. This preform 501 comprises a neck 502, aneck ring 503, a cylindrical body 505, and a bottom 506. At a heightrange excluding the neck 502 and the bottom 506, an intermediate layer513 of the nylon resin having a gas barrier property is sandwichedbetween an outer layer 511 and an inner layer 512 both made of the PETresin.

A DOCUMENT OF CONVENTIONAL ART Patent Document

-   Patent document 1: Published patent application JP1989-254539

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In the case of the biaxially drawn, blow molded bottle having a gasbarrier resin, such as a nylon resin, laminated with the layers of themain PET resin material, the PET resin layers are in tight contact withthe layer of the gas barrier resin, but they are not adhered to eachother. If the bottle is filled with a carbonated beverage, and thus, ifthe inside is put under a pressurized condition, the bottle has noproblem as long as the inside is under pressure before use. However, inthe moment when the cap is removed, both types of layers may happen tobe peeled from each other because of the action of large shearing forcecaused by a rapid change in pressure. Once both types of layers havebeen peeled, they never come in tight contact again. Since lightscatters or reflects at the peeled interface, the peeling can beobserved from outside. Therefore, there occurs a problem of impairedouter appearance. In addition, during a shrinking process after thebiaxially drawing and blow molding, a delamination problem may alsooccur due to a difference in the ratio of shrinkage between theintermediate layer and the outer or inner layer.

A problem to be solved by this invention is to control theabove-described problem of delamination in the laminated and biaxiallydrawn, blow molded bottle. Objects of this invention are to provide alaminated synthetic resin bottle effectively protected againstdelamination, to provide a process for molding a laminated preform whichis used to mold this laminated bottle, and to provide an injectionmolding device to be used to mold the laminated preform.

Means of Solving the Problems

Regarding the laminated and biaxially drawn, blow molded synthetic resinbottle, the process for molding a laminated preform used to mold thislaminated bottle, and the injection molding device used to mold thelaminated preform, description will be made below in the order of thelaminated synthetic resin bottle, the injection molding device, and theprocess for molding the laminated preform. Among the features of thisinvention that has been made to solve the above-described technicalproblems, a main feature associated with the laminated synthetic resinbottle is a bottle obtained by biaxially drawing and blow molding alaminated synthetic resin preform in the shape of a test tube, in whichsubstrate layers of the main resin have been laminated with at least anintermediate layer. The intermediate layer is laminated with thesubstrate layers over a predetermined height range, but narrow verticalconnecting zones having no intermediate layer and having the substratelayers welded directly with each other are formed in parallel in acircumferential direction and in a plural number along an axialdirection of the bottle, and are disposed on both right and left sidesof each intermediate layer segment to be formed, thus allowing theintermediate layer to be segmentalized in the circumferential directionby these vertical connecting zones.

According to the above-described feature, the intermediate layer issegmentalized in the circumferential direction by the verticalconnecting zones having the substrate layers welded directly with eachother, and two vertical connecting zones are disposed on both the rightand left sides of each neighboring intermediate layer segment. At thattime, when the shearing force acts on the interface between theintermediate layer and the substrate layers, the force would act onlyunder a condition that both right and left sides of each intermediatelayer segment are restricted by the vertical connecting zones. Becauseof this restriction, the delamination between layers is effectivelyprevented from occurring.

The laminated layers comprising the substrate layers and theintermediate layer or layers can be varied in their laminate structures,including, for example, 2 resins-3 layers (a substrate-an intermediate-asubstrate), 2 resins-5 layers (a substrate-an intermediate-a substrateR-an intermediate-a substrate), 3 resins-4 layers (a substrate-asubstrate A-an intermediate B-a substrate), 3 resins-4 layers (asubstrate-a substrate R-an intermediate-a substrate), 3 resins-5 layers(a substrate-an intermediate A-a substrate-an intermediate B-asubstrate), and 3 resins-5 layers (a substrate-an intermediate-asubstrate R-an intermediate-a substrate). Even in a case where more thanone intermediate layer is formed, these intermediate layers can also besegmentalized in the circumferential direction by the verticalconnecting zones having the substrate layers directly joined and welded,because these vertical connecting zones are formed similarly in parallelin the circumferential direction and in a plural number along the axialdirection of the bottle, and are disposed on both the right and leftsides of each intermediate layer segment to be formed. In the abovedescription, the intermediate layer A and the intermediate layer B areshown to be made of different resins, and the substrate R indicates thatit is the layer made of a recycled main resin product.

In addition to the main feature described above, another feature of thisinvention associated with the laminated synthetic resin bottle is thatnot only the vertical connecting zones are extended over a predeterminedheight range, but that narrow horizontal connecting zones having nointermediate layer and having the substrate layers are welded directlywith each other are formed in parallel in the axial direction and in aplural number along the circumferential direction of the bottle, and aredisposed on both upper and lower sides of each intermediate layersegment to be formed, to divide the intermediate layer laterally. Thus,the intermediate layer is segmentalized in a lattice pattern in thecircumferential and axial directions by both the vertical and horizontalconnecting zones

Because of the above feature, the intermediate layer is dividedvertically and horizontally into segments by the vertical and horizontalconnecting zones having the main resin substrates joined and weldedtogether. The shearing force acting on the interface between thesubstrate layers and the intermediate layer should be restricted alongthe right and left edges by the vertical connecting zones, and inaddition, along the upper and lower edges by the horizontal connectingzones. Due to this lattice pattern, the delamination between layers, ascaused by the change in pressure inside the bottle, can be effectivelyprevented from occurring.

In addition to the above features, still another feature of thisinvention associated with the laminated synthetic resin bottle is that abody portion, except for the neck and the bottom, is included in thepredetermined height range.

Measurement values on the bottle formation include the height range overwhich the intermediate layer is laminated, and the number and/or widthof the vertical or horizontal connecting zones. These values can bedetermined properly by taking into account the purpose of bottle use,the functions of the intermediate layer, such as the gas barrierproperty, and moldability (or productivity) of preforms or bottlesmanufactured by using the preforms as the primary molded products. Theintermediate layer can be laminated over the entire height range of thebottle. However, the neck is a portion which is not drawn in the biaxialdrawing and blow molding, and the bottom is a portion which is not fullydrawn. These portions tend to be deformed by laminating the intermediatelayer. Unless the intermediate layer is laminated in the neck and bottomportions, then problems of damaged sealing property of the neck fittedwith a cap or damaged uprightness of the bottom can be effectivelycontrolled.

In addition to the above features, still another feature associated withthe laminated synthetic resin bottle is that the laminated layerscomprises main resin layers and an intermediate layer of a gas barrierresin and have a laminate structure of 2 resins and 3 layers.

The above feature is intended to increase the gas barrier property ofthe bottle by using a gas barrier resin as the intermediate layer.Typical layer structure includes, for example, PET/a nylon resin, suchas MXD-6/PET, PET/EVOH/PET, PP/EVOH/PP, and PLA/PGA/PLA where EVOH is anethylene vinyl alcohol copolymer; PP, a polypropylene resin; PLA,polylactic acid; and PGA, polyglycolic acid.

For the purpose of further improving the barrier property of theintermediate layer made of a gas barrier resin, an oxygen scavenger oran oxygen absorber can be mixed with or scattered in the gas barrierresin. It is also possible to scatter a lamellar silicate in the MXD-6nylon resin to produce a nano composite material. The intermediate layerof a cyclic polyolefin resin is effective as a barrier resin againstwater.

A main feature of this invention associated with the injection moldingdevice is that an injection molding device is used to injection mold alaminated preform in a test-tube shape, which is biaxially drawn andblow molded into the bottle and which comprises substrate layers of amain resin and at least an intermediate layer. This injection moldingdevice comprises two resin feeders to feed the main resin and theintermediate-layer resin, a multi-nozzle section in which to laminatethe main resin with the intermediate-layer resin, and a mold for moldingthe preform. The multi-nozzle section comprises at least threelayer-forming flow channels: cylindrical inner and outer flow channelsto form the substrate layers of the main resin and a cylindrical middleflow channel located between the inner flow channel and the outer flowchannel to form the intermediate layer from an intermediate-layer resin.Downstream of at least three layer-forming flow channels, a joined flowchannel is disposed by way of a confluence where molten resins joinafter having flowed through respective layer-forming flow channels. Atsome points ranging from a given position along the middle flow channel,through which the intermediate-layer resin flows, to the confluence, aplural number of vertical blocking rib pieces are disposed in parallelin the circumferential direction so as to cross the middle flow channel.These vertical blocking rib pieces divide the flow through the middlechannel into multiple streams along the circumferential direction.

According to the injection molding device having the above-describedfeature, the cylindrical intermediate-layer resin flowing through thismiddle flow channel can be segmentalized in the circumferentialdirection, by a plural number of vertical blocking rib pieces disposedin parallel in the circumferential direction and at some points rangingfrom a given position along the middle flow channel to the confluence.The intermediate layer can be laminated with the substrate layers undera circumferentially segmentalized condition. After the intermediatelayer has been segmentalized, the two layers of the main resin havingflowed through the inner and outer flow channels are joined and weldedtogether to form the vertical connecting zones.

The above feature of the injection molding device enables theintermediate layer to be sandwiched by the substrate layers on bothsurfaces of the intermediate layer. The laminated preform can also haveother laminate structures, such as 2 resins-3 layers, 2 resins-5 layers,3 resins-4 layers, or 3 resins-5 layers, by adding another suitablefeeder or more cylindrical flow channels to the multi-nozzle section.

A main feature of this invention associated with the process for moldingthe laminated preform is a process utilizing a injection molding deviceto mold a laminated preform in the shape of a test tube for use in thebiaxial drawing and blow molding. The laminated preform to be molded hassubstrate layers and an intermediate layer laminated with the substratelayers in a predetermined height range. In addition, narrow verticalconnecting zones having no intermediate layer and having the substratelayers joined and welded directly with each other are formed in parallelin the circumferential direction and in a plural number along the axialdirection of the bottle, and are disposed on both the right and leftsides of each of the intermediate layer segments to be formed. Thus, theintermediate layer is segmentalized by the vertical connecting zones inthe circumferential direction. The injection molding device used in thisprocess has a multi-nozzle section which laminates the substrate layersmade of a main resin with the intermediate layer made of anintermediate-layer resin. The nozzle section is provided withcylindrical flow channels through which the main resin is flowed for apredetermined time span to form the substrate layers, and with acylindrical flow channel through which an intermediate-layer resincoming from another feeder is flowed concurrently for a certain limitedtime during this predetermined time span to form the intermediate layer.The intermediate-layer resin is segmentalized in the latter flow channelin the circumferential direction, and this segmentalized resin joins themain resin at the confluence in a manner that the intermediate-layerresin is sandwiched between the substrate layers of the main resin. Themold cavity is filled with this laminated molten resin fluid.

According to the above-described molding process, the intermediate-layerresin is segmentalized in the circumferential direction inside thecylindrical flow channel used to form the intermediate layer. Thecircumferentially segmentalized intermediate layer is then laminatedbetween the substrate layers. In those portions having no intermediatelayer as a result of segmentalization, both substrate layers are weldedtogether. Thus, it is possible for the laminated and injection moldedpreform to have the vertical connecting zones made of welded substratelayers and formed in the axial direction. The laminated synthetic resinbottle can be obtained by biaxially drawing and blow molding thislaminated preform having the intermediate layer segmentalized in thecircumferential direction by the vertical connecting zones of thisinvention.

According to the main feature associated with the molding process, thelaminated preform has vertical connecting zones in the given heightrange. In addition, another feature of this invention associated withthe molding process is that narrow horizontal connecting zones having nointermediate layer and having the substrate layers welded directly witheach other are formed in parallel in the axial direction and in a pluralnumber along the circumferential direction of the prefrom, and aredisposed along the upper and lower sides of each intermediate layersegment to be formed, thus allowing the intermediate layer to besegmentalized by both the vertical and horizontal connecting zones inthe circumferential direction and in the axial direction. Theintermediate-layer resin is supplied to the cylindrical middle flowchannel intermittently from another feeder for a certain limited timewithin a predetermined time span to form the horizontally segmentalizedintermediate layer.

With the cylindrical middle flow channel being supplied with theintermediate-layer resin intermittently but simultaneously from anotherfeeder for a certain period of time within a predetermined time span,the above molding process enables the separately flowed main resin to belaminated directly with each other in the circumferential directionduring the time zones when the supplies of the intermediate-layer resinhave been discontinued. As a result, the injection-molded laminatedpreform is provided with horizontal connecting zones formed in parallelin the axial direction and disposed in a number corresponding to thefrequency of discontinuation.

Thus, there can be molded the laminated preform in a laminate structurewherein the horizontal and vertical connecting zones having thesubstrate layers directly welded are formed over a given height range inparallel in the circumferential and axial directions and wherein theintermediate layer is segmentalized vertically and horizontally by boththe vertical and horizontal connecting zones.

The laminated bottle can be obtained by biaxially drawing and blowmolding such a laminated preform. Corresponding to the laminatestructure of the intermediate layer of this laminated preform, thebottle has the intermediate layer segmentalized by a plural number ofthe horizontal and vertical connecting zones having the substrate layersjoined and welded with each other are formed in the circumferentialdirection and in the axial direction over a predetermined height range.

Still another feature of the process for molding the laminated preformof this invention is that the injection molding device of this inventiondescribed above is utilized according to the main feature of the processfor molding the laminated preform of this invention. The main resincoming from a feeder to form substrate layers are supplied to the innerflow channel and the outer flow channel. The intermediate resin comingfrom another feeder to form the intermediate layer is supplied to themiddle flow channel. The intermediate-layer resin is segmentalized inthe circumferential direction by vertical blocking rib pieces existinginside the middle flow channel. At the confluence, theintermediate-layer resin under the circumferentially segmentalizedcondition is flowed between the main resin flows coming respectivelyfrom the inner and outer flow channels so that a laminated molten resinfluid is formed at the confluence.

According to the above molding process, the cylindricalintermediate-layer resin flowing through the middle flow channel can besegmentalized circumferentially, and the segmentalized intermediatelayer can be laminated between two substrate layers, by using a pluralnumber of vertical blocking rib pieces, which are formed in parallel inthe circumferential direction of the middle flow channel, and aredisposed at some point along the way ranging from a predeterminedposition of the middle flow channel to the confluence inside themulti-nozzle section of the injection molding device to be used. Thelaminated preform to be injection molded has a segmentalizedintermediate layer, and in portions where there is no intermediatelayer, the substrate layers are directly joined and welded together. Thevertical connecting zones are thus formed in parallel in thecircumferential direction, and are disposed along the axial direction ina plural number corresponding to the number of the vertical blocking ribpieces. The synthetic resin laminated bottle can be obtained bybiaxially drawing and blow molding this laminated preform in which theintermediate layer has been segmentalized in the circumferentialdirection by the vertical connecting zones.

Still another feature of the process for molding the laminated preformof this invention is that the main resin that forms the substrate layersis supplied from a feeder to the inner and outer flow channels at agiven pressure or velocity for a predetermined time span while theintermediate-layer resin is simultaneously supplied from another feederto the middle flow channel for a certain limited time within thepredetermined time span to form the intermediate layer.

This process of supplying the main resin to the inner and outer flowchannels for a predetermined time span and simultaneously supplying theintermediate-layer resin from another feeder to the middle flow channelfor a certain limited time within the predetermined time span is aso-called simultaneous injection process. The intermediate layer can belaminated over a predetermined height range of the preform byappropriately setting the time to start the supply of theintermediate-layer resin to the middle flow channel and the time to stopthe supply.

Still another feature of the process for molding the laminated preformof this invention is that the predetermined height range covers a bodyportion excluding the neck and the bottom.

Measurement aspects of forming the intermediate layer, such as theheight range for laminating the intermediate layer, the numbers andwidth of the vertical and/or horizontal connecting zones, etc., can bearbitrarily determined, taking into account the purpose of bottle use,the function of the intermediate layer such as a gas barrier property,and/or moldability and productivity of the preform and of the bottlemade from this preform. The intermediate layer may also be laminatedover all the height range of the bottle. The preform neck is a portionnever drawn during the biaxial drawing and blow molding operation, andthe bottom is a portion not fully drawn. Problems of the low capacity ofseal with a cap caused by a deformed neck and a low standing functioncaused by bottom deformation can be effectively prevented in thebiaxially drawn, blow molded bottom made from this preform, by notlaminating the intermediate layer in the neck and bottom portions of thepreform.

Still another feature of the process for molding the laminated preformof this invention is that the preform has a laminate structure of tworesins and three layers comprising a main resin and a gas barrier resinthat forms the intermediate layer.

The above feature is intended to give the bottle an improved gas barrierproperty. Typically, the layer structure includes, for example,PET/MXD-6 or another nylon resin/PET, PET/EVOH/PET, PP/EVOH/PP, andPLA/PGA/PLA, where EVOH is an ethylene vinyl alcohol copolymer, PP is apolypropylene resin, PLA is polylactic acid, and PGA is polyglycolicacid.

For the purpose of further improving the barrier property of theintermediate layer made of a gas barrier resin, an oxygen scavenger oran oxygen absorber can be mixed with or scattered in the gas barrierresin. It is also possible to scatter a lamellar silicate in the MXD-6nylon resin to produce a nano composite material. The intermediate layerof a cyclic polyolefin resin is effective as a barrier resin againstwater.

Effects of the Invention

This invention having the above-described features has the followingeffects:

According to the features of the invention associated with a biaxiallydrawn, blow molded bottle of this invention, the intermediate layer issegmentalized in the circumferential direction by the verticalconnecting zones in which the substrate layers are joined and weldedtogether, or segmentalized by both the vertical and horizontalconnecting zones in the circumferential direction and in the axialdirection. Because of this segmentalization, the shearing force acts onthe interfaces between the intermediate layer and the substrate layersunder a condition that each segment of the intermediate layer is tieddown by the vertical connecting zones on the right and left sides and byboth the vertical and horizontal connecting zones on the upper and lowersides as well as on the right and left sides. Thus, the delaminationcaused by molding shrinkage or pressure changes inside the bottle can beeffectively prevented from occurring.

According to the features of the invention associated with the injectionmolding device of this invention, the intermediate-layer resin flowsthrough the middle flow channel, and at some points ranging from a givenposition along the middle flow channel to the confluence, a pluralnumber of vertical blocking rib pieces are disposed in parallel in thecircumferential direction. These vertical blocking rib pieces divide thecylindrical intermediate-layer resin flowing through the middle channelinto multiple streams separated in the circumferential direction. Theintermediate layer in the circumferentially segmentalized state can belaminated between the substrate layers. Meanwhile, in the portionssandwiched between the separated streams of the intermediate-layerresin, the two substrate layers of main resin coming from the inner andouter flow channels are directly joined and thermally welded.

According to the features of the invention associated with the processfor molding the laminated preform of this invention, the intermediatelayer is segmentalized in the circumferential direction in a cylindricalflow channel through which the intermediate-layer resin flows. Thecircumferentially segmentalized intermediate layer is then laminatedbetween inner and outer substrate layers. In those portions having nointermediate layer as a result of segmentalization, both inner and outersubstrate layers are directly welded together. Vertical connecting zonesderived from welded substrate layers can be formed in parallel in thecircumferential direction and disposed in a plural number along theaxial direction of the laminated preform that has been injection molded.Furthermore, by supplying the cylindrical middle flow channel with theintermediate-layer resin intermittently but simultaneously from anotherfeeder, the separately flowed main resin layers can be directly weldedat the confluence in the circumferential direction during the time zoneswhen the supplies of the intermediate-layer resin have beendiscontinued. As a result, the injection-molded and laminated preform isprovided with a plural number of horizontal connecting zones in whichthe substrate layers have been welded together. The horizontalconnecting zones are formed in parallel in the circumferential directionand in the axial direction in a plural number corresponding to thefrequency of discontinuation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the bottle in the first embodiment of thisinvention.

FIG. 2 is a plane cross-section of the bottle taken along line A-A shownin FIG. 1.

FIG. 3 is a front view, with a partial vertical section, of thelaminated preform molded by the molding process of this invention andused to mold the bottle shown in FIG. 1.

FIG. 4 is a plane cross-section of the preform taken along line B-Bshown in FIG. 3.

FIG. 5 is a vertical section of an embodiment of the multi-nozzlesection of the injection molding device of this invention.

FIG. 6 is a vertical section of the multi-nozzle section of FIG. 5combined with a hot runner block.

FIG. 7 is a plane cross-section of the multi-nozzle section taken alongline C-C shown in FIG. 6.

FIG. 8 is an explanatory diagram showing an example of injection patternfor molding the preform of FIG. 3.

FIG. 9 is explanatory diagrams showing a manner in which the mold cavityis filled with molten resins in the injection pattern of FIG. 8.

FIG. 10( a) is a front view of the bottle in the second embodiment ofthis invention; and FIG. 10( b), a vertical section showing a pattern ofthe intermediate layer laminated in the axial direction.

FIG. 11 is a plane cross section of the bottle in the second embodimenttaken along line A-A in FIG. 10.

FIG. 12 is a front view, with a partial vertical section, of thelaminated preform molded by the molding process of this invention andused to mold the bottle of FIG. 10.

FIG. 13 is a plane cross-section of the preform of FIG. 12 taken alongline B-B in FIG. 12.

FIG. 14 is a vertical section showing the multi-nozzle section of theinjection molding device used to form the preform of FIG. 12.

FIG. 15 is a vertical section showing the multi-nozzle section of FIG.14 combined with the hot runner block.

FIG. 16 is a plane cross-section of the multi-nozzle section taken alongline C-C in FIG. 15.

FIG. 17 is an explanatory diagram showing an example of the injectionpattern for molding the preform of FIG. 12.

FIG. 18 is explanatory diagrams showing a manner in which the moldcavity is filled with molten resins in the injection pattern of FIG. 17.

FIG. 19( a)(b)(c) are partial plane cross sections showing otherexamples of the laminate structure of the bottle associated with themolding process of this invention.

FIG. 20 is a front view of a laminated bottle of prior art.

FIG. 21 is a front view, with a partial vertical section, of thelaminated preform of prior art.

PREFERRED EMBODIMENTS OF THE INVENTION

The biaxially drawn, blow molded, and laminated synthetic resin bottle,the injection molding device, and the process for molding the laminatedpreform by using this injection molding device of this invention arefurther described with respect to preferred embodiments, now referringto the drawings. FIGS. 1 and 2 show the laminated synthetic resin bottlein the first embodiment of this invention, in which FIG. 1 is a frontview, and FIG. 2 is a plane cross-section taken along line A-A shown inFIG. 1. The bottle is a so-called pressure PET bottle made by using aPET resin as the main resin, and is used for beverages containing acarbonate ingredient. The bottle 201 comprises a neck 202, a neck ring203, a shoulder 204, a cylindrical body 205, and a bottom 206 of apetaloid type having multiple extended feet.

This bottle 201 has a laminate structure over a given height range h2 (aheight ranging from right beneath a lower end of the neck ring 203 to anupper end of the bottom 206). As shown in the plane cross-section ofFIG. 2, the intermediate layer 213 is laminated between the outer layer211 and the inner layer 212, both of which are the substrate layers of amain resin, such as a PET resin. On the other hand, the intermediatelayer 213 is made of a gas barrier resin, such as a polyxylylene diamineadipamide (MXD6 nylon) resin. In addition, as shown in FIG. 2, thisintermediate layer 213 is segmentalized in the circumferential directionby the vertical connecting zones 214 a, which are formed in parallel inthe circumferential direction of the bottle 201 and in a plural number(16 zones in this embodiment) along the axial direction or in thevertical direction, and are disposed on both the right and left sides ofeach intermediate layer segment to be formed, by joining and welding theouter layer 211 and the inner layer 212 together. It is noted in thefront view of FIG. 1 that the bottle 201 shows eight vertical connectingzones 214 a in the height range h2 extending from right beneath the neckring 203 to the upper end of the bottom 206. As shown, the segments ofthe intermediate layer 213 are hatched for the convenience of easyunderstanding. Actually, however, the segments of the intermediate layer213 are in tight contact with the substrate layers, i.e., with the outerlayer 211 and the inner layer 212, and thus, the bottle 201 lookstransparent in its outer appearance.

The user wants to sip a drink from a laminated PET pressure bottle ofthis kind made in conventional art, but at the instant when he/seeremoved the cap, there would be a drastic pressure drop inside thebottle, and the body wall would rapidly deform into a caved state. Withthis rapid deformation, the shearing force would act on the interfacebetween the intermediate layer 213 and the outer layer 211 and/or theinner layer 212. Since the intermediate layer 213 of a nylon resin is intight contact with, but not adhered to, the outer layer 211 or the innerlayer 212 of a PET resin, there occurs the delamination, and theappearance of the bottle would be impaired now that the delaminationbecomes visible from the scattering or reflection of light at thedelaminated portions.

On the other hand, the laminated bottle 201 in this embodiment producesan action-and-effect of the vertical connecting zones 214 a by which theintermediate layer 213 is segmentalized in the circumferentialdirection. Even under a drastic pressure drop described above, thebottle can withstand the delamination effectively and maintain atransparent condition and good outer appearance. It is considered thatthe action-and-effect of the vertical connecting zones to protect thebottle against delamination is produced because the layers deform in ashort span between two neighboring vertical connecting zones 214 a inthe laminate structure comprising an outer substrate layer 211/anintermediate layer 213/an inner substrate layer 212. Each span wouldhave the limited shearing force acting on the interfaces between layersand thus, a limited degree of deformation.

FIGS. 3 and 4 show the laminated preform 101, that is, a primary moldedproduct to be biaxial drawn and blow molded into the laminated bottle201 in the above embodiment. FIG. 3 is a front view with a partialvertical cross-section; and FIG. 4, a plane cross-section taken alongline B-B shown in FIG. 3. This laminated preform 101 is made of a PETresin as the main resin material, and has a shape of a test tubecomprising a neck 102, a neck ring 103, a cylindrical body 105, and abottom 106.

The preform 101 has a laminate structure in which the intermediate layer113 extends over a given height range h1 (extending from right beneaththe neck ring 103 to an upper end of the bottom 106 in this embodiment).In this height range, the intermediate layer 113 made of a gas barrierresin, such as polyxylylene diamine adipamide (MXD6 nylon), is laminatedbetween the outer layer 111 and the inner layer 112, which are thesubstrate layers made of the main resin comprising a PET resin, as shownin the plane cross-section of FIG. 4. As can be seen in FIG. 4, thisintermediate layer 113 is segmentalized in the circumferential directionby the vertical connecting zones 114 a, formed in parallel in thecircumferential direction and in a plural number (16 zones in thisembodiment) along the centrally axial direction, by joining and weldingtogether the outer and inner substrate layers 111, 112.

Next, the process for injection molding the laminated preform 101 willbe described below with respect to a preferred embodiment. The laminatedpreform 101 to be molded has the intermediate layer 113 segmentalized inthe circumferential direction by the above-described vertical connectingzones 114 a. FIGS. 5-7 show an example of the injection molding deviceof this invention, in which important parts are outlined. FIG. 5 is avertical section showing an example of a multi-nozzle section 11, with amold 1 fitted in the downstream. FIG. 6 is a vertical section of themulti-nozzle section 11 of FIG. 5, to which a hot runner block 21 isfitted in the upstream. FIG. 7 is a plane cross-section of themulti-nozzle section 11 taken along line C-C shown in FIG. 6.

This injection molding device comprises resin feeders A, B, whichseparately supply the device with two types of different resins in amolten state, the multi-nozzle section 11 where two molten resins arelaminated, and the mold 1 to form the preform. The multi-nozzle section11 comprises three layer-forming flow channels: a cylindrical inner flowchannel 15 and a cylindrical outer flow channel 17 to form the substratelayers of the main resin and a cylindrical middle flow channel 16 toform the intermediate layer. Downstream of these three layer-formingflow channels, a joined cylindrical flow channel 19 is disposed by wayof a confluence 18 where molten resins join after having flowed throughthe respective layer-forming flow channels.

At some points ranging from a given position along the middle flowchannel 16 to the confluence 18, vertical blocking rib pieces 16R aredisposed in parallel in the circumferential direction and in a pluralnumber (16 in this embodiment) to divide the flow through the middlechannel 16 into multiple streams in the circumferential direction. Theplane cross-section of FIG. 7 shows the layout of a plural number of thevertical blocking rib pieces 16R disposed in parallel in thecircumferential direction. As shown, 16 vertical blocking rib pieces 16Rare disposed at an equal central angle and in the circumferentialdirection so as to cross the middle flow channel 16.

More specifically, the inner flow channel 15, the middle flow channel16, and the outer flow channel 17 are all cylindrical, and are formed bya shut-off pin 20 and ring mandrels 24 c, 24 d, and 24 e, which aredisposed from inside outwards in a coaxial core state. The verticalblocking rib pieces 16R are set so as to cross the middle flow channel16 under a condition that through-slits 24 cs penetrate through the wallof the ring mandrel 24 c, with outer end faces of the through-slits 24cs coming in contact with the inner peripheral wall of the ring mandrel24 d on the outside. The cylindrical middle flow channel 16 is thussegmentalized in the circumferential direction to form multiple,vertical streams.

Next, an explanation is given as to the process steps for molding thelaminated preform 101 of FIGS. 3 and 4 by using this injection moldingdevice. PET, the main resin, supplied from the feeder A, is fed from thefeed port 22 a, and is passed through the feed channel 23 a inside thehot runner. A nylon resin, the intermediate-layer resin, supplied fromthe feeder B, is fed from the feed port 22 b, and is passed through thefeed channel 23 b. The two resins are fed to the multi-nozzle section 11at a predetermined timing. Then, the two resins are joined in thismulti-nozzle section 11, and the cavity 1 a of the mold 1 is filled withthe joined resins (See FIG. 6).

The above resin feeders A and B that can be used in this inventioninclude, for example, an extruder of a screw type, an accumulator havinga plunger fitted at the end of the extruder, and the like.

A check valve 25 having a back-flow prevention function by means of aball valve is disposed in the neighborhood of a point of connection tothe multi-nozzle section 11 along the feed channel 23 b through whichthe intermediate-layer resin flows. This check valve 25 can also bedisposed in the multi-nozzle section 11 rather than along the feedchannel 23 b.

The main resin that has passed through the feed channel 23 a now entersa guiding channel 12 a. From here, the main resin is diverted into thecylindrical inner flow channel 15 and the cylindrical outer flow channel17 by means of two manifolds 14 a 1 and 14 a 2. The intermediate-layerresin that has passed through the feed channel 23 b now enters a guidingchannel 12 b. From here, the intermediate-layer resin is passed throughthe cylindrical middle flow channel 16 by means of a manifold 14 b.

At the confluence 18, the intermediate-layer resin from the middle flowchannel 16 is made to flow between the main resin from the inner flowchannel 15 and the main resin from the outer flow channel 17. Amulti-layer molten resin fluid is formed inside the joined flow channel19 for a certain limited time, with the intermediate-layer resin beingin the shape of an intermediate layer disposed in a coaxial core statebetween the layers of the main resin. The multi-layer fluid is injectedinto the cavity 1 a of the mold 1 to fill the cavity with the fluid. Itis noted here that the intermediate-layer resin has been formed insidethe middle flow channel 16 so as to have a cylindrical shape, but thatthe resin is segmentalized in the circumferential direction by a pluralnumber of vertical blocking rib pieces 16R which are disposed on thedownstream side in parallel in the circumferential direction. Thus, theintermediate layer is laminated in a segmentalized state between thelayers of the main resin.

FIG. 8 shows an example of injection pattern for the main resin and theintermediate-layer resin to mold the preform 101 shown in FIG. 3. FIG. 8shows an outline of the injection pattern, with horizontal axis servingas the time axis, and longitudinal axis, as the injection speed. Thisinjection pattern is one of the so-called simultaneous injection moldingpatterns. FIG. 9( a)-(c) are explanatory diagrams showing the flow ofresins fed into the cavity 1 a based on this injection pattern.

FIG. 9( a) shows a state in which the cavity 1 a has been supplied onlywith the main resin, and the timing is just before point E in theinjection pattern. At point E, the injection of the intermediate-layerresin starts. Over the range from point E to point F, the cavity 1 a isfilled with the resins in a laminated state where the intermediate-layerresin is sandwiched between layers of the main resin (See FIG. 9( b)).At point F, the injection of the intermediate-layer resin comes to ahalt, and again, the cavity 1 a is supplied only with the main resin,and then the injection process comes to an end (See FIG. 9( c)). In thisway, the preform 101 can be obtained in which the intermediate layer hasbeen laminated in a predetermined height range h1, as shown in FIG. 3.At that time, the intermediate-layer resin supply can be started andstopped, respectively, at points E and F in high precision and in ashort time, by using the check valve 25 fitted to the feed channel 23 bthrough which the intermediate-layer resin is fed. Thus, the heightrange h1 can be positioned very precisely.

According to the injection pattern shown in FIG. 8, the main resin issimultaneously injection-molded with the intermediate-layer resin.However, it is also possible to suspend tentatively the injection of themain resin that has been injected before, to inject only theintermediate-layer resin, and then to inject only the main resin in asequential manner.

FIGS. 10 and 11 show the laminated synthetic resin bottle in the secondembodiment of this invention. FIG. 10( a) is a front view; and FIG. 10(b), a vertical section showing a pattern of intermediate layer laminatedin the axial direction. FIG. 11 is a plane cross-section taken from lineA-A shown in FIG. 10. This bottle 201 is a so-called pressure PET bottlemade of a PET resin as the main resin and used for beverages containinga carbonate ingredient. The bottle 201 comprises a neck 202, a neck ring203, a shoulder 204, a cylindrical body 205, and a bottom 206 in aso-called petaloid shape having multiple projecting feet.

The bottle 201 has a laminate structure over a predetermined heightrange h2 (from right beneath the lower end of the neck ring 203 to anupper end of the bottom 206 in this embodiment), as shown in FIGS. 10(b) and 11. In this structure, the intermediate layer 213 made of apolyxylylene diamine adipamide resin (MXD6 nylon) having a gas barrierproperty is laminated between the outer layer 211 and the inner layer212, both of which are the substrates of a PET resin serving as the mainresin.

As can be seen in FIG. 10( b), the intermediate layer 213 issegmentalized in the predetermined height range h2 by horizontalconnecting zones 214 p, which are formed in parallel in the axialdirection of the bottle 201 and in a plural number (5 zones in thisembodiment) along the circumferential direction, by connecting directlythe outer substrate layer 211 to the inner substrate layer 212.Furthermore, as can be seen in FIG. 11, the intermediate layer 213 isalso segmentalized by the vertical connecting zones 214 a, which areformed in parallel in the circumferential direction and in a pluralnumber (16 zones in this embodiment) along the axial direction of thebottle 201, by connecting directly the outer layer 211 to the innerlayer 212.

As can be seen in the front view of FIG. 10( a), the intermediate layer213 is laminated between the outer layer 211 and the inner layer 212 ina state in which the layer is divided into segments in a rectangularshape, with four sides of each segment being surrounded by adjacenthorizontal connecting zones 214 p and adjacent vertical connecting zones214 a. At an upper end, the intermediate layer 213 is connected to theneck 202 including the neck ring 203 where no intermediate layer 213 islaminated. At a lower end, the intermediate layer 213 is connected tothe bottom 206 having no intermediate layer 213. The front view of FIG.10 shows cross-hatched segments as the areas where the intermediatelayer 213 is laminated. Actually, however, the intermediate layer 213 isin tight contact with both the outer layer 211 and the inner layer 212,and the bottle is transparent in appearance.

If the user remove the cap from a prior-art laminated pressure PETbottle of this type to take a sip, then the body wall would bedrastically caved in with rapid pressure drop inside the bottle.

This drastic deformation would cause the shearing force to act on theinterfaces between the intermediate layer 213 of a nylon resin and theouter layer 211 and/or the inner layer 212 of a PET resin. Since theselayers are in tight contact but are not adhered to one another,delamination would take place, and becomes visible from scattering orreflection of light at the peeled.

On the other hand, in the case of the laminated bottle 201 of thisembodiment, an action-and-effect can be attained by both the horizontalconnecting zones 214 p and the vertical connecting zones 214 a, whichmake the intermediate layer 213 segmentalized in the axial andcircumferential directions. Even under a sharp pressure drop describedabove, the delamination can be prevented effectively from occurring, andthe bottle can maintain good, transparent appearance. Theaction-and-effect of the horizontal connecting zones 214 p and thevertical connecting zones 214 a to prevent the above-describeddelamination is considered to work in the following manner: Under thelaminate structure comprising an outer substrate layer 211, anintermediate layer 213, and an inner substrate layer 212, theintermediate layer 213 deforms only in short spans partitioned byadjacent horizontal connecting zones 214 p and adjacent verticalconnecting zones 214 a. The extent of deformation is thus limited tosmall segments of the intermediate layer 213 partitioned by theseconnecting zones. The shearing force action on the interfaces, too, islikely to be limited.

FIGS. 12 and 13 show the laminated preform, which is a primary moldedproduct to be biaxially drawn and blow molded into the laminated bottle201 of FIG. 10 and which is injection molded by the molding process ofthis invention later described. FIG. 12 is a front view with a part in avertical section. FIG. 13 is a plane cross-section of the laminatedpreform taken from line B-B shown in FIG. 12. This preform 101 is madeof a PET resin as the main material, has a shape of a test tube, andcomprises a neck 102, a neck ring 103, a cylindrical body 105, and abottom 106.

This preform 101 has a laminate structure in which an intermediate layer113 of a polyxylylene diamine adipamide (MXD6 nylon) having a gasbarrier property is laminated between an outer layer 111 and an innerlayer 112, both of which are substrate layers of a PET resin used as themain resin, as shown in the plane cross-section of FIG. 13, and isdisposed in a predetermined height range h1 (from right beneath the neckring 103 to an upper end of the bottom 106 in this embodiment).

As shown in the vertical section in FIG. 12, the intermediate layer 113is segmentalized in the axial direction by the horizontal connectingzones 114 p, which are formed in parallel in the axial direction of thepreform 101 and in a plural number (5 zones in this embodiment) alongthe circumferential direction, by joining and welding the outersubstrate layer 111 and the inner substrate layer 112 together. As shownin FIG. 12, the intermediate layer 113 is also segmentalized in thecircumferential direction by the vertical connecting zones 114 a, whichare formed in parallel in the circumferential direction and in a pluralnumber (16 zones in this embodiment) along the axial direction, byjoining and welding the outer substrate layer 111 and the innersubstrate layer 112 together.

The process for molding the laminated preform 101 will be described withrespect to its preferred embodiment, in which the intermediate layer 113has been segmentalized in both the axial and circumferential directionsby the horizontal connecting zones 114 p and the vertical connectingzones 114 a described above. FIGS. 14-16 show an outlined important partof the injection molding device used to mold the laminated preform 101of FIG. 12. FIG. 14 is a vertical section showing an example of themulti-nozzle section 11 to which the mold 1 has been fitted on thedownstream side. FIG. 15 is a vertical section showing the multi-nozzlesection 11 of FIG. 14, to which the hot runner block 21 has been fittedon the upstream side. FIG. 16 is a plane cross-section of themulti-nozzle section 11, taken along line C-C shown in FIG. 15. It isnoted here that the multi-nozzle section 11 shown in FIGS. 14 and 16 isstructurally similar to that shown in FIGS. 5 and 7, but that themulti-nozzle section 11 shown in FIGS. 14 and 16 differs from that shownin FIGS. 5 and 7 in that the check valve 25 has been disposed in the hotrunner block 21 of FIG. 6 while the check valve 25 is not used in thiscase, as shown in FIG. 15.

Next, process steps using the above-described injection molding devicewill be described in the case of the process for molding the laminatedpreform of this invention, associated with the laminated preform 101shown in FIGS. 12 and 13. The PET resin, a main resin, is supplied fromthe resin feeder A, is passed through the feed port 22 a and the feedchannel 23 a inside the hot runner, and is sent to the multi-nozzlesection 11. The nylon resin, an intermediate-layer resin, is suppliedfrom the resin feeder B, is passed through the feed port 22 b and thefeed channel 23 b, and sent to the multi-nozzle section 11 at apredetermined timing. The resins join together in the multi-nozzlesection 11, and two resins (three layers) are fed into the cavity 1 a ofthe mold 1 (See FIG. 15).

The main resin is passed through the feed channel 23 a and the guidechannel 12 a, and is divided into the cylindrical inner channel 15 andthe cylindrical outer channel 17 by means of respective manifolds 14 a 1and 14 a 2. The intermediate-layer channel is passed through the feedchannel 23 b and the guide channel 12 b, and is led into the middle flowchannel 16 by means of the manifold 14 b.

At the confluence 18, the flow of the intermediate-layer resin from themiddle flow channel 16 is sandwiched by the layers of the main resincoming from the inner flow channel 15 and the outer flow channel 17.Inside the joined flow channel 19, a column-shape multi-layer moltenresin fluid is formed so that the intermediate layer coaxially disposedbetween the layers of the main resin, and this fluid is injected intothe cavity 1 a of the mold 1 to fill the cavity therewith. At that time,the intermediate-layer resin formed cylindrically in the middle flowchannel 16 is segmentalized in the circumferential direction by thevertical blocking rib pieces 16R, which are disposed on the downstreamside in parallel in the circumferential direction of the preform and ina plural number. The intermediate-layer resin in segments is laminatedbetween layers of the main resin, and thus, vertical connecting zones114 a are formed in the body of the laminated preform 101, as shown inFIGS. 12 and 13.

Next, FIG. 17 is an exemplified injection pattern for the main resin andthe intermediate-layer resin to mold the preform 101 shown in FIG. 12,with horizontal axis serving as the time axis, and longitudinal axis, asthe injection speed. This injection pattern is one of the so-calledsimultaneous injection molding patterns. In this example, the start andstop of injection of the intermediate-layer resin are repeated at giventime intervals (repeated 6 times in this embodiment). Thus, theintermediate-layer resin is intermittently supplied to the middle flowchannel 16 to obtain segmentalized intermediate layer 113.

FIG. 18( a)-(c) are explanatory diagrams showing the flow of resins fedinto the cavity 1 a, based on this injection pattern. FIG. 18( a) showsa state of injection right before point E of the injection pattern. Inthis state, only the main resin has been fed. At point E, intermittentinjections of the intermediate-layer resin get started. Between points Eand F, the intermediate-layer resin is laminated between the layers ofthe main resin, but the resin is segmentalized in the circumferentialdirection by the above-described vertical blocking rib pieces 16R, andis also segmentalized in the axial direction in accordance with theinjection pattern shown in FIG. 17. Then, the mold cavity 1 a is filledwith the laminate having a grid pattern of segments (See FIG. 18( b)).At point F, the injection of the barrier resin comes to an end, and fromthen on, only the main resin is fed again to finish the injectionprocess (See FIG. 18( c)), and thus, the laminated preform 101 ismolded. The horizontal connecting zones 114 p of the laminated preform101 shown in FIG. 12 are formed by the process steps based on theinjection pattern of FIG. 17.

The laminated preform 101 thus obtained has a laminate structure inwhich the intermediate layer 113 has been segmentalized horizontally andvertically by the horizontal connecting zones 114 p and by the verticalconnecting zones 114 a that are formed by the vertical blocking ribpieces 16R.

In order for the supplies of the intermediate-layer resin to be startedand stopped according to the injection pattern of FIG. 17, in apredetermined time span, in high precision, and instantaneously, andespecially in order for the resin supply to be cut at once at the timeof stoppage, it is effective to use a so-called pullback methodinvolving setting back the screw in an instant at the intermediate-layerresin feeder B.

This invention including the biaxially drawn, blow molded syntheticresin bottle, the injection molding device, and the process for moldingthe laminated preform have been described with respect to preferredembodiments. However, it is to be understood that this invention shouldnot be construed as limitative to these embodiments. For example, thelaminated bottle in the above embodiment of this invention has alaminate structure of 2 resins and 3 layers, as shown in planecross-section of FIG. 2 or 11, but if necessary, the bottle may havevarious other laminate structures. FIGS. 19( a)-(c) show other examplesof laminate structures for the laminated bottle of this invention in theplane cross-sections similar to FIG. 2 or FIG. 11. These (a), (b), and(c) show the following laminate structures in the order of layers fromoutside to inside:

(a) A laminate of 3 resins and 5 layers comprising: A substrate layer211/An intermediate layer 213/A substrate layer 211R made of a recycledresin/An intermediate layer 213/A substrate layer 212.

(b) A laminate of 3 resins and 5 layers comprising: A substrate layer211/An intermediate layer 213A/A substrate layer 211/Anotherintermediate layer 213B/A substrate layer 212.

(c) A laminate of 3 resins and 4 layers comprising: A substrate layer211/An intermediate layer 213A/Another intermediate layer 213B/Asubstrate layer 212.

Under these laminate structures, too, the intermediate layer or layersis/are segmentalized by the vertical connecting zones 114 a that arederived from the substrate layers and are disposed on both sides of eachvertical segment of the intermediate layer.

Vertical connecting zones 214 a are set at a number of 16 zones in theembodiment for the laminated bottle of FIG. 1. However, measurementvalues such as the number and/or width of vertical or horizontalconnecting zones can be determined properly by taking into account thepurpose of bottle use, the functions of the intermediate layer, such asthe gas barrier property, and productivity of the preforms or thebottles manufactured using the preforms as the primary molded products.

The second embodiment of the laminated bottle of FIG. 10 shows 5horizontal connecting zones 114 p and 16 vertical connecting zones 114a. The measurement values such as the number and/or width of theseconnecting zones can also be determined properly by taking into accountthe purpose of bottle use, the functions of the intermediate layer, suchas the gas barrier property, and moldability (or productivity) of thepreforms or the bottles manufactured using the preforms as the primarymolded products.

In the embodiment of the laminated bottle 201 of FIG. 1 or FIG. 10, boththe horizontal connecting zones 214 p and the vertical connecting zones214 a are disposed at a regular interval. These zones need not always bedisposed at a regular interval, but the interval can be appropriatelyadjusted so that some areas may have a narrow interval, if delaminationtends to occur more frequently in those areas than in other areas.

The preferred embodiments have been described above as a round bottle,but the bottle may be a square bottle as well. Since in that case, thebottle shape is not isotropic, the positions of a plural number ofvertical connecting zones are not set at an equal central angle, but aredetermined by giving consideration to an angle position or positionswhere delamination tends to occur.

In the above embodiments, a PET resin was used as the main resin, and anylon resin, as the intermediate-layer resin, but various combinationsof synthetic resins can be used, taking into consideration the purposeof bottle use, moldability, and the function desired for theintermediate layer.

INDUSTRIAL APPLICABILITY

According to this invention, it is easy to obtain a bottle having alaminate structure in which the intermediate layer is segmentalized bythe vertical and/or horizontal connecting zones. Such a bottle enablesdelamination of the intermediate layer from the outer layer and/or theinner layer to be controlled effectively when the delamination takesplace as caused by molding shrinkage, pressure changes inside thebottle, and the like. The bottle of this invention is expected to have awide application of use in the field of carbonate beverages.

DESCRIPTION OF REFERENCE SIGNS

-   1. Mold-   1 a. Cavity-   11. Multi-nozzle section-   12 a. Guide channel for the main resin-   12 b. Guide channel for the intermediate-layer resin-   14 a 1, 14 a 2, 14 b. Manifold-   15. Inner flow channel-   16. Middle flow channel-   16R. Vertical blocking rib pieces-   17. Outer flow channel-   18. Confluence-   19. Joined flow channel-   20. Shut-off pin-   21. Hot runner block-   22 a. Main resin feed port-   22 b. Intermediate resin feed port-   23 a. Feed channel-   23 b. Feed channel-   24 c, 24 d, 24 e. Ring mandrel-   24 cs. Through-slit-   25. Check valve-   A. Main resin feeder-   B. Intermediate-layer resin feeder-   101, 501. Preform-   102, 502. Neck-   103, 503. Neck ring-   105, 505. Body-   106, 506. Bottom-   111, 511. Outer substrate layer-   112, 512. Inner substrate layer-   113, 513. Intermediate layer-   114 p. Horizontal connecting zone-   114 a. Vertical connecting zone-   h1. Height range-   201, 601. Bottle-   202, 602. Neck-   203, 603. Neck ring-   204, 604. Shoulder-   205, 605. Body-   206, 606. Bottom-   211, 611. Outer substrate layer-   212, 612. Inner substrate layer-   213 (213A, 213B), 613. Intermediate layer-   214 p. Horizontal connecting zone-   214 a. Vertical connecting zone-   h2. Height range

What is claimed is:
 1. An injection molding device for injection moldinga laminated preform that: (i) is in a test-tube shape, (ii) hassubstrate layers of a main resin and at least an intermediate layer, and(iii) is for use in biaxial drawing and blow molding, said injectionmolding device comprising: two resin feeders configured to feed the mainresin and at least a resin for forming an intermediate layer, amulti-nozzle section in which to laminate the main resin with theintermediate-layer resin, and a mold for molding the preform, whereinthe multi-nozzle section comprises at least three layer-forming flowchannels: a cylindrical inner flow channel and a cylindrical outer flowchannel to form the substrate layers of the main resin, a cylindricalmiddle flow channel located between the inner flow channel and the outerflow channel to form the intermediate layer, and a joined flow channeldisposed downstream of at least three layer-forming flow channels and byway of a confluence where molten resins join after having flowed throughrespective layer-forming flow channels; and wherein at some pointsranging from a given position along the cylindrical middle flow channelto the confluence, a plural number of vertical blocking rib pieces aredisposed in parallel in the circumferential direction so as to cross thecylindrical middle flow channel and to divide the flow through thecylindrical middle channel into multiple streams along thecircumferential direction.
 2. A process for molding a laminated preformby an injection molding device, said preform: (i) being in a test-tubeshape and for use in biaxial drawing and blow molding, (ii) havingsubstrate layers and an intermediate layer laminated between thesubstrate layers in a given height range, and (iii) having such alaminate structure that narrow vertical connecting zones having nointermediate layer and having substrate layers welded directly with eachother are formed in parallel in a circumferential direction and in aplural number along an axial direction of the preform and are disposedon both right and left sides of each intermediate layer segment to beformed in this height range, thus allowing the intermediate layer to besegmentalized in the circumferential direction by these verticalconnecting zones, the process comprising the steps of: (i) providing aninjection molding device having a multi-nozzle section configured tolaminate the substrate layers made of a main resin with an intermediatelayer made of an intermediate-layer resin, (ii) supplying a cylindricalinner flow channel and a cylindrical outer flow channel inside themulti-nozzle section with the main resin for a predetermined time spanto form substrate layers, while at the same time, supplying acylindrical middle flow channel with an intermediate-layer resin comingfrom another feeder for a certain limited time during this predeterminedtime span to form the intermediate layer, (iii) dividing theintermediate-layer resin inside the cylindrical middle flow channel intomultiple streams in a circumferential direction, (iv) joining thecircumferentially segmentalized intermediate-layer resin in a mannerthat the intermediate-layer resin is sandwiched between the substratelayers of the main resin at the confluence to form a laminated moltenresin fluid, and (v) filling a mold cavity with the laminated moltenresin fluid.
 3. The process for molding the laminated preform accordingto claim 2, wherein the laminated preform has vertical connecting zonesin the given height range, and also has such a laminate structure thatnarrow horizontal connecting zones having no intermediate layer andhaving the substrate layers welded directly with each other are formedin parallel in the axial direction and in a plural number along thecircumferential direction of the preform and are disposed along upperand lower sides of each intermediate layer segment to be formed, thusallowing the intermediate layer to be segmentalized by both the verticalconnecting zones and the horizontal connecting zones in thecircumferential direction and in the axial direction, and wherein theintermediate-layer resin is simultaneously supplied from another feederto the cylindrical middle flow channel, in which the intermediate layeris formed, but is supplied intermittently for a certain limited timeduring the predetermined time span to have the intermediate layersegmentalized horizontally.
 4. The process for molding the laminatedpreform according to claim 2, further comprising the steps of: (i)supplying the cylindrical inner flow channel and the cylindrical outerflow channel with a main resin coming from a feeder to form substratelayers, (ii) supplying the cylindrical middle flow channel with anintermediate-layer resin from another feeder to form the intermediatelayer, (iii) dividing the intermediate-layer resin intermittently in thecircumferential direction by means of vertical blocking rib piecesdisposed inside the cylindrical middle flow channel, and (iv) at theconfluence, allowing the intermediate-layer resin to flow in such a wayas to be sandwiched between the main resin flows respectively comingfrom the cylindrical inner flow channel and the cylindrical outer flowchannel under a circumferentially segmentalized condition so that alaminated molten resin fluid is formed in the joined flow channel,wherein the injection molding device is an injection molding device tobe used to injection mold a laminated preform, which is in a test-tubeshape, has substrate layers of a main resin and at least an intermediatelayer, and is used in biaxial drawing and blow molding, said injectionmolding device comprising two resin feeders to feed the main resin andat least a resin for forming an intermediate layer, a multi-nozzlesection in which to laminate the main resin with the intermediate-layerresin, and a mold for molding the preform, wherein the multi-nozzlesection comprises at least three layer-forming flow channels: thecylindrical inner flow channel and the cylindrical outer flow channelform the substrate layers of the main resin, the cylindrical middle flowchannel located between the cylindrical inner flow channel and the outercylindrical flow channel form the intermediate layer, and the joinedflow channel disposed downstream of at least three layer-forming flowchannels and by way of a confluence where molten resins join afterhaving flowed through respective layer-forming flow channels, andwherein at some points ranging from a given position along thecylindrical middle flow channel to the confluence, a plural number ofvertical blocking rib pieces are disposed in parallel in thecircumferential direction so as to cross the cylindrical middle flowchannel and to divide the flow through the cylindrical middle channelinto multiple streams along the circumferential direction.
 5. Theprocess for molding the laminated preform according to claim 3, furthercomprising the steps of: (i) supplying the cylindrical inner flowchannel and the cylindrical outer flow channel with a main resin comingfrom a feeder to form substrate layers, (ii) supplying the cylindricalmiddle flow channel with an intermediate-layer resin from another feederto form the intermediate layer, (iii) dividing the intermediate-layerresin intermittently in the circumferential direction by means ofvertical blocking rib pieces disposed inside the cylindrical middle flowchannel, and (iv) at the confluence, allowing the intermediate-layerresin to flow in such a way as to be sandwiched between the main resinflows respectively coming from the cylindrical inner flow channel andthe cylindrical outer flow channel under a circumferentiallysegmentalized condition so that a laminated molten resin fluid is formedin the joined flow channel, wherein the injection molding device is aninjection molding device to be used to injection mold a laminatedpreform, which is in a test-tube shape, has substrate layers of a mainresin and at least an intermediate layer, and is used in biaxial drawingand blow molding, said injection molding device comprising two resinfeeders to feed the main resin and at least a resin for forming anintermediate layer, a multi-nozzle section in which to laminate the mainresin with the intermediate-layer resin, and a mold for molding thepreform, wherein the multi-nozzle section comprises at least threelayer-forming flow channels: the cylindrical inner flow channel and thecylindrical outer flow channel form the substrate layers of the mainresin, the cylindrical middle flow channel located between thecylindrical inner flow channel and the outer cylindrical flow channelform the intermediate layer, and the joined flow channel disposeddownstream of at least three layer-forming flow channels and by way of aconfluence where molten resins join after having flowed throughrespective layer-forming flow channels, and wherein at some pointsranging from a given position along the cylindrical middle flow channelto the confluence, a plural number of vertical blocking rib pieces aredisposed in parallel in the circumferential direction so as to cross thecylindrical middle flow channel and to divide the flow through thecylindrical middle channel into multiple streams along thecircumferential direction.
 6. The process for molding the laminatedpreform for use in the biaxial drawing and blow molding, according toclaim 4, wherein the main resin that forms the substrate layers issupplied from the feeder to the inner flow channel and the outer flowchannel at a given pressure or velocity for a predetermined time span,while the intermediate-layer resin is simultaneously supplied fromanother feeder to the cylindrical middle flow channel for a certainlimited time within the predetermined time span to form the intermediatelayer.
 7. The process for molding the laminated preform for use in thebiaxial drawing and blow molding, according to claim 5, wherein the mainresin that forms the substrate layers is supplied from the feeder to theinner flow channel and the outer flow channel at a given pressure orvelocity for a predetermined time span, while the intermediate-layerresin is simultaneously supplied from another feeder to the cylindricalmiddle flow channel for a certain limited time within the predeterminedtime span to form the intermediate layer.
 8. The process for molding thelaminated preform according to claim 2, wherein a predetermined heightrange covers a body portion excluding the neck and the bottom of theperform.
 9. The process for molding the laminated preform according toclaim 3, wherein a predetermined height range covers a body portionexcluding the neck and the bottom of the perform.
 10. The process formolding the laminated preform according to claim 4, wherein apredetermined height range covers a body portion excluding the neck andthe bottom of the perform.
 11. The process for molding the laminatedpreform according to claim 5, wherein a predetermined height rangecovers a body portion excluding the neck and the bottom of the perform.12. The process for molding the laminated preform according to claim 6,wherein a predetermined height range covers a body portion excluding theneck and the bottom of the perform.
 13. The process for molding thelaminated preform according to claim 7, wherein a predetermined heightrange covers a body portion excluding the neck and the bottom of theperform.
 14. The process for molding the laminated preform according toclaim 2, wherein the preform has a laminate structure of two resins andthree layers comprising a main resin and a gas barrier resin that formsthe intermediate layer.
 15. The process for molding the laminatedpreform according to claim 3, wherein the preform has a laminatestructure of two resins and three layers comprising a main resin and agas barrier resin that forms the intermediate layer.
 16. The process formolding the laminated preform according to claim 4, wherein the preformhas a laminate structure of two resins and three layers comprising amain resin and a gas barrier resin that forms the intermediate layer.17. The process for molding the laminated preform according to claim 5,wherein the preform has a laminate structure of two resins and threelayers comprising a main resin and a gas barrier resin that forms theintermediate layer.
 18. The process for molding the laminated preformaccording to claim 6, wherein the preform has a laminate structure oftwo resins and three layers comprising a main resin and a gas barrierresin that forms the intermediate layer.
 19. The process for molding thelaminated preform according to claim 7, wherein the preform has alaminate structure of two resins and three layers comprising a mainresin and a gas barrier resin that forms the intermediate layer.
 20. Theprocess for molding the laminated preform according to claim 8, whereinthe preform has a laminate structure of two resins and three layerscomprising a main resin and a gas barrier resin that forms theintermediate layer.